Is the event something you need to attend for work? If so, and I know you haven't had a whole lot of luck with them in the past, I'd probably take it higher in the university. Otherwise, depending on the relationship with this person and my level of comfort, I'd either tell them how disappointed and upset I am that they are not willing to modify the event so I can participate and/or be all passive aggressive with them when I was forced to deal with them in the future. I'm sorry people are continuing to be ****** towards you. F this person.